After you remove the four screws that hold the smokebox/boil and cab onto the motor block, you then only have to remove the screws from the top cover of the motor block to access the motor, gears, and two lead weights. But to access the large lead weight inside the smokebox/boiler, you must break the old glue seal between the smokebox and boiler. I use a utility knief blade and small hammer placed into the grove along the brass ring that separates the smokebox from the boiler.......and continually tap around the grove until it breaks the glue seal. There are two screws in the bottom of the large lead weight that hold it in place.......and you pull it out the front of the boiler.
I soak overnight the lead weights in either cleaning vinigar or CLR solvent, then after washing them off and drying, I spray them with the GB Spray Liquid Tape Electrical to prevent future oxidation. Some of the lead the old LGB company used was inferior and prone to oxidation.
You're going to have to flush the motor block to clean out all that oxidation specks from the gears, sidewalls, etc. I had to do this recently with a customer's Mogul that also was a mess with lead oxidation specks all over the place, even on th outside of the Mogul. I use plastic safe CRC QD Electronic Cleaner with the small straw nossel to clean out the motor block. Wear gloves and don't break that lead oxidation stuff........wear a mask.......it's hazardous to us humans!
Use only gear grease suitable for LGB locomotive gears. I use and sell the Massoth 8319401 Gear Lubricant, 1.8 oz tube. I sell it for $12 plus $4.50 USPS First Class Package shipping.
You can email me directly if you need help reassemblying your Mogul........I can also send you some photo by email that show the position of things.
Tom White
Olddominionrailways@gmail.com